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Message-Id: <20100423095528.668decf8.randy.dunlap@oracle.com>
Date: Fri, 23 Apr 2010 09:55:28 -0700
From: Randy Dunlap <randy.dunlap@...cle.com>
To: Chase Douglas <chase.douglas@...onical.com>
Cc: linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH] Add documentation for trace commands mod,
traceon/traceoff
On Fri, 23 Apr 2010 12:17:47 -0400 Chase Douglas wrote:
> The mod command went in as commit
> 64e7c440618998fd69eee6ab490b042d12248021
>
> The traceon/traceoff commands when in as commit
> 23b4ff3aa479c9e3bb23cb6b2d0a97878399784a
>
> Signed-off-by: Chase Douglas <chase.douglas@...onical.com>
> ---
> Documentation/trace/ftrace.txt | 35 +++++++++++++++++++++++++++++++++++
> 1 files changed, 35 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
> index 03485bf..64e08d5 100644
> --- a/Documentation/trace/ftrace.txt
> +++ b/Documentation/trace/ftrace.txt
> @@ -155,6 +155,9 @@ of ftrace. Here is a list of some of the key files:
> to be traced. Echoing names of functions into this file
> will limit the trace to only those functions.
>
> + This interface also allows for commands to be used. See the
> + "Filter commands" section for more details.
> +
> set_ftrace_notrace:
>
> This has an effect opposite to that of
> @@ -1822,6 +1825,38 @@ this special filter via:
> echo > set_graph_function
>
>
> +Filter commands
> +---------------
> +
> +A few commands are supported by the set_ftrace_filter interface.
> +Trace commands have the following format:
> +
> +<function>:<command>:<parameter>
> +
> +The following commands are supported:
> +
> +- mod
> + This command enables function filtering per module. The
> + parameter defines the module. For example, if only the write*
> + functions in the ext3 module are useful in a trace, echo
> + 'write*:mod:ext3' > set_ftrace_filter. This command interacts
Can we have the echo command all on one line, please? E.g.:
+ parameter defines the module. For example, if only the write*
+ functions in the ext3 module are useful in a trace, use:
+ echo 'write*:mod:ext3' > set_ftrace_filter
+ This command interacts
> + with the filter in the same way as filtering based on function
> + names. Thus, adding more functions in a different module is
> + accomplished by appending (>>) to the filter file. Remove
> + specific module functions by prepending '!'
> + (!writeback*:mod:ext3).
> +
> +- traceon/traceoff
> + These commands turn tracing on and off when the specified
> + functions are hit. The parameter determines how many times the
> + tracing system is turned on and off. If unspecified, there is
> + no limit. For example, to disable tracing when a schedule bug
> + is hit the first 5 times, use '__schedule_bug:traceoff:5'.
> + These commands are cumulative whether or not they are appended
> + to set_ftrace_filter. To remove a command, prepend it by '!'
> + and drop the parameter (!__schedule_bug:traceoff).
> +
> +
> trace_pipe
> ----------
---
~Randy
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